Effect of some phenolic carboxylic acids on cherimoya (Annona cherimolia) polyphenoloxidase activity

Abstract

Aliphatic carboxylic acids did not affect cherimoya (Annona cherimolia Mill) epicarp polyphenoloxidase activity. Benzoic, isovunillic, cinnamic, pcoumaric, salicylic and 3-hydroxybenzoic acids inhibited the oxidation of catechol and the hydroxylation of tyramine catalysed by cherimoya epicarp poiyphenoloxidase; caffeic and ferulic acids activated the oxidation of catechol; protocatechuic and syringic acids activated the hydroxylation of tyramine. The minimal structural requirement of a phenolic compound to be an inhibitor of cherimoya polyphenoloxidase was the association of a carboxylic group and a benzene nucleus. The inhibitory strength was greater when a conjugated double bond was located between the carboxylic group and the benzene nucleus. Replacement of more than one hydrogen in the aromatic nucleus by rithrr hydroxpl or niethoxyl groups decreased the eflectiveness as inhibitors, and, in some cases, led to an activation of the two charucteristic reactions of cherimoya epicarp polyphenoloxidase.

Non-specific binding sites help to explain mixed inhibition in mushroom tyrosinase activities

“…Studies on the structural requirements for a potent tyrosinase inhibitor led scientists to molecules such as benzoic acid and CA. A benzene ring carrying an unsaturated open chain with a carboxylic terminal showed inhibitory potential as important as that observed for benzoic acid [13,29]. Shi et al…”

“…There are some reports on the effects of molecules carrying CAFG on tyrosinase activities [10,13,29,30]. Although the role of CAFG has not been clearly explained, the ability to chelate the copper ions has been considered important [30].…”

Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase

“…Aliphatic carboxylic acids do not affect cherimoya (A. cherimolia Mill) epicarp polyphenol oxidase activity [9].…”

“…Benzoic, isovanillic, cinnamic, p-coumaric, salicylic and 3-hydroxybenzoic acids inhibit the oxidation of catechol and the hydroxylation of tyramine catalyzed by cherimoya epicarp polyphenol oxidase [9]. Caffeic and ferulic acids activate the oxidation of catechol; protocatechuic and syringic acids activate the hydroxylation of tyramine [9].…”

“…Benzoic, isovanillic, cinnamic, p-coumaric, salicylic and 3-hydroxybenzoic acids inhibit the oxidation of catechol and the hydroxylation of tyramine catalyzed by cherimoya epicarp polyphenol oxidase [9]. Caffeic and ferulic acids activate the oxidation of catechol; protocatechuic and syringic acids activate the hydroxylation of tyramine [9]. Aromatic carboxylic acid inhibition on o-diphenol oxidase from sweet cherry fruits was reduced by esterification or by replacing the benzene ring with an aliphatic or heterocyclic group, but not by replacing it with a highly unsaturated open chain [10].…”